Winding Device

ABSTRACT

A winding device generally includes a spool, which includes a shaft, a sleeve rotatably coupled to the shaft such that the sleeve and the shaft are capable of partial independent rotation relative to one another, with the sleeve adapted to receive thereon a core onto which a web of material may be wound, and one or more gripping members, which are adapted to engage the core upon relative rotation of the shaft in a first direction, and disengage the core upon relative rotation of the shaft in a second direction.

BACKGROUND OF THE INVENTION

The present invention relates to a winding device for winding a web ofmaterial onto a core and, more particularly, to an improved windingdevice for webs comprising inflated cushioning material.

Various machines for forming inflated cushioning material are known,which produce inflated cushioning from a web of un-inflated material byinflating and sealing closed gas-containing chambers within thematerial. Such cushioning is used to package items, by wrapping theitems in the cushions and placing the wrapped items in a shippingcarton, or simply placing one or more inflated cushions inside of ashipping carton along with an item to be shipped. The cushions protectthe packaged item by absorbing impacts that may otherwise be fullytransmitted to the packaged item during transit, and also restrictmovement of the packaged item within the carton to further reduce thelikelihood of damage to the item. At the same time, the end-user caninflate and use as desired, without having to store large volumes ofpre-inflated cushioning material.

In many instances, it is desired to inflate cushioning material, andstore small quantities of the material for subsequent use, typically bywinding the inflated material into a roll. Existing winding devices forthis purpose are not as efficient or convenient as would otherwise bedesired.

Accordingly, there remains a need in the art for improved web-windingdevices, which are more effective and easier for operators to use.

SUMMARY OF THE INVENTION

Those needs are met by the present invention, which, in one aspect,provides a winding device comprising a spool, the spool comprising:

a. a shaft;

b. a sleeve rotatably coupled to the shaft such that the sleeve and theshaft are capable of partial independent rotation relative to oneanother, the sleeve enclosing at least a portion of the shaft andadapted to receive thereon a core, onto which a web of material may bewound; and

c. one or more gripping members, which are adapted to engage the coreupon relative rotation of the shaft in a first direction, whereby thecore rotates with the shaft to allow the web to be wound onto the core,the gripping members being further adapted to disengage the core uponrelative rotation of the shaft in a second direction, whereby the coremay be removed from the sleeve.

A further aspect of the invention is directed to a winding devicecomprising a spool, said spool comprising:

a. a shaft;

b. a sleeve rotatably coupled to the shaft such that the sleeve and theshaft are capable of partial independent rotation relative to oneanother, the sleeve enclosing at least a portion of the shaft andadapted to receive thereon a web of material such that the web may bewound onto the sleeve; and

c. one or more gripping members, which are adapted to engage the webupon relative rotation of the shaft in a first direction, whereby theweb rotates with the shaft and is thereby wound into a roll on thesleeve, the gripping members being further adapted to disengage the webupon relative rotation of the shaft in a second direction, whereby theroll may be removed from the sleeve.

Yet another aspect of the invention is directed to a winding device,comprising:

a. a spool adapted to receive thereon a core, onto which a web ofmaterial may be wound, the web being supplied to the spool at apredetermined speed;

b. a drive mechanism coupled to the spool to drive the rotation thereofat a predetermined rotational speed;

c. a sensor, which monitors the rotational speed of the spool andgenerates a signal indicative of the rotational speed; and

d. a controller in communication with the sensor to receive the signalas a first input, the controller also receiving, as a second input, anindication of the speed at which the web is supplied to the spool,wherein, the controller calculates a diameter of the web as it is woundonto the core.

These and other aspects and features of the invention may be betterunderstood with reference to the following description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a system having an inflation/sealingapparatus that produces a web of inflated cushioning material, and awinding device in accordance with the present invention for winding theweb onto a core;

FIG. 2 is a partial perspective view of the winding device shown in FIG.1, featuring a spool and a core that may be received on the spool;

FIG. 3 is a partially-exploded perspective view of the spool shown inFIG. 2;

FIG. 4 is a cross-sectional view of the spool shown in FIG. 2;

FIG. 5 is a frontal, elevational view of the spool, showing the grippingmembers of the spool moving from a disengagement position to anengagement position;

FIG. 6 is similar to FIG. 5, except taken along lines 6-6 in FIG. 4 toshow the gripping members in the engagement position;

FIG. 7 is similar to FIG. 6, except showing the gripping members movingfrom the engagement position to the disengagement position;

FIG. 8 is a schematic view of a control system for the winding device;and

FIG. 9 is a plan view of the inflated cushioning material as shown inFIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a system 10 for inflating, sealing, and winding a web12 of material into a roll 14. Roll 14 is shown in phantom for clarity.System 10 generally includes an inflation and sealing apparatus 16 and awinding device 18. The inflation/sealing apparatus 16 may be anysuitable device for producing a web, e.g., of inflated cushioningmaterial, as described, e.g., in U.S. Pat. No. 7,220,476 or in U.S.Publication No. US 2010-0251665 A1, the disclosures of which are herebyincorporated herein by reference thereto. As further described in theforegoing references and illustrated in FIG. 9, the web 12 produced byapparatus 16 may be an inflated cushioning material 20. Inflatedcushioning material 20 may be formed from two superposed film sheets 19,and may include rows of inflated chambers 22, wherein each of thechambers 22 has at least one change in width over their length, e.g.,with two inflatable sections of relatively large width 24 connected byrelatively narrow inflatable passageways 26. As shown, the largesections 24 may be substantially spherical or hemispherical in shape,e.g., resembling bubbles or the like. Cushioning material 20 may furtherinclude inflation ports 28 located at a proximal end of each chamber 22,with the inflation ports being formed by intermittent seals 30 betweenthe sheets 19. As each chamber 22 is inflated, apparatus 16 continuouslyforms a seal line 31 at the corresponding inflation port 28 to enclosethe inflation gas within each chamber. As shown in FIG. 1, un-inflatedweb 32 may be supplied to the inflation/sealing apparatus 16 in the formof a roll 34, which is then conveyed through the apparatus via suitabledrive rollers or the like, wherein the chambers 22 are sequentially andcontinuously inflated and sealed closed, to produce the inflatedcushioning material 20 as shown in FIG. 9.

It should be understood that the present invention is not limited toinflatable webs of the type as described above, but may be used with anyweb that can be wound onto a core, e.g., thermoplastic film, paper, etc.

Winding device 18 may include a base 36, a stanchion 38, and a spool 40,extending in cantilevered fashion from stanchion 38. In someembodiments, a drive mechanism, e.g., a motor (not shown), may be housedin base 36, with suitable mechanical linkage (not shown) in stanchion 38to join the drive mechanism to the spool 40, e.g., a belt, chain, geartrain, etc. In such embodiments, an on/off switch 42 for the motor maybe provided, e.g., on stanchion 38 (see FIG. 2).

As shown in FIGS. 2-4, spool 40 may include a shaft 44, a sleeve 46, andone or more gripping members 48. In the illustrated embodiment, four (4)such gripping members 48 are included in spool 40. As will be explainedin further detail below, sleeve 46 is rotatably coupled to shaft 44,such that the sleeve and shaft are capable of partial independentrotation relative to one another. Further, sleeve 46 encloses at least aportion of the shaft 44, and is adapted to receive thereon a core 50,onto which web 12, e.g., comprising inflated cushioning material 20, maybe wound (see also FIG. 1). As shown, shaft 44 may be coupled to sleeve46 via a rotary mounting bracket 52. As also shown, a sleeve extensionmember 53 may be affixed to spool 40, e.g., at rotary mounting bracket52. Such extension member 53 may be included as necessary to accommodatethe length of core 50, e.g., such that the resultant sleeve-length ofthe spool 40 may approximate that of the core 50. In this manner, coresof various lengths, corresponding to webs 12 of various widths, may beaccommodated by winding device 18. The extension member 53 may furtherinclude an end-cap 55, which may have a rounded outer surface in orderto facilitate the placement of a core 50 on sleeve 46, as extended bymember 53, as shown in FIG. 2.

Referring now to FIGS. 5-7, the operation of spool 40 will be describedin further detail. As noted above, sleeve 46 is rotatably coupled toshaft 44, such that the sleeve and shaft are capable of partialindependent rotation relative to one another. Moreover, gripping members48 are adapted to engage a core 50 received on sleeve 46, upon relativerotation of shaft 44 in a first direction. FIGS. 5-6 illustrate thesefeatures. In FIG. 5, a core 50 (shown in phantom) has been placed oversleeve 46 as shown in FIG. 2. FIGS. 5-6 illustrate a sequence of eventsby which the gripping members 48 engage the core upon relative rotationof shaft 44 in first direction 54, whereby the core 50 rotates withshaft 44, i.e., also in first direction 54, to allow the web 12 to bewound onto the core, e.g., as shown in FIG. 1. As shown in FIG. 7,gripping members 48 are further adapted to disengage the core 50 uponrelative rotation of shaft 44 in a second direction 56, whereby the core50 may be removed from sleeve 46, e.g., when roll 14 of web 12 hasreached a desired size.

Gripping members 48 are adapted, i.e., structured and arranged, to bothengage and disengage the core, based on the coupled relationship betweenthe shaft 44 and sleeve 46, wherein the shaft and sleeve are capable ofpartial independent rotation relative to one another. In someembodiments, this may be achieved when shaft 44 is rotatably mounted inrotary mounting bracket 52, and the bracket 52 is affixed to sleeve 46,e.g., via fasteners 58 (FIGS. 3-4). Fasteners 58 may be in the form ofscrews (as illustrated), welded joints, etc. Shaft 44 may include abushing 60 or the like to facilitate rotational movement of the shaftagainst the bracket 52, e.g., against an inner surface of the bracket asillustrated.

The gripping members 48 may be attached to shaft 44, e.g., at the distalend 62 thereof. In the illustrated embodiment, distal end 62 of shaft 44is relatively wide to accommodate four (4) gripping members 48, and isin the form of a platform, which is affixed to an end region 64 of shaft44. Other arrangements are, of course, also possible, such as a wideneddistal end 62 being integral with shaft 44; the distal end 62 not beingwidened, e.g., the same diameter as the rest of shaft 44; a greater orlesser number of gripping members 48; etc.

As shown in FIG. 5, the gripping members 48 may have a proximal end 67and a distal end 68, wherein the proximal end 67 is attached to shaft44, e.g., at the distal end 62 thereof. The attachment of the grippingmembers 48 to shaft 44 may be a pivotal attachment, i.e., such that thegripping members 48 are pivotally attached at proximal end 67 to theshaft, e.g., via pivotal fasteners 69.

Accordingly, a part, e.g., distal end 68, of each gripping member 48 maymove in the direction of arrow 66 (FIG. 5) away from shaft 44 and intoan engagement position (FIG. 6), in which the gripping members engagethe core 50, when shaft 44 rotates in first direction 54. Such movement66 may generally be a rotation-to-translation type of movement, as willbe described in further detail below, as produced by the rotation ofshaft 44 in first direction 54, and facilitated by the pivotalattachment of gripping members 48 to shaft 44. Similarly, as shown inFIG. 7, the part, e.g., distal end 68, of the gripping members 48 thatare in the engagement position of FIG. 6, may also move in the directionof arrow 70 towards the shaft 44 and into a disengagement position, inwhich the gripping members disengage the core 50, when the shaft 44rotates in second direction 56.

As shown in FIGS. 3-7, rotary mounting bracket 52 may include one ormore guide slots 72. Further, each of the gripping members 48 mayinclude a guide pin 74, which is movable within a corresponding one ofthe guide slots 72. As will be explained in further detail below, theguide slots and guide pins cooperate to facilitate movement of thegripping members 48 into the engagement position shown in FIG. 6, andalso the return movement of the gripping members into the disengagementposition shown in FIG. 7.

In the illustrated embodiment, slots 72 provide a substantially linearpath, and are positioned at an angle relative to a radial directionextending from the center of shaft 44 and outwards towards sleeve 46.Further, the gripping members 48 are pivotally attached at theirproximal end 67 to shaft 44, with guide pins 74 being spaced frompivotal fasteners 69 and moving within a corresponding one the guideslots 72. With such an arrangement, it may be seen from FIGS. 5-7 thatthe rotational movement of shaft 44 is converted into translationalmovement by the distal ends 68 of the gripping members 48. Thus, distalends 68 of the gripping members move away from shaft 44 in direction 66,and into the engagement position shown in FIG. 6, when the shaft rotatesin first direction 54, as guide pins 74 move translationally in guideslots 72 in the direction of arrow 76 (FIG. 5). In the reversesituation, i.e., when it is desired to remove roll 14 from spool 40,distal ends 68 of the gripping members move towards shaft 44 in thereturn direction 70, and into the disengagement position shown in FIG.7, when the shaft rotates in opposing second direction 56, as guide pins74 move translationally in guide slots 72 in the direction of arrow 78(FIG. 7), which is the reverse of direction 76 (FIG. 5).

As noted above, sleeve 46 is rotatably coupled to shaft 44, such thatthe sleeve and shaft are capable of partial independent rotationrelative to one another. The partial nature of such relative rotation isperhaps best shown in FIG. 6, wherein the guide pins 74 have reached theouter ends 80 of the guide slots 72. As shown, the outer ends 80 serveto prevent further outward travel of the pins 74 in slots 72, and thusalso further outward movement of the distal ends 68 of gripping members48. Because the gripping members are attached to shaft 44 (at proximalends 67), at the point where the pins 74 reach the outer ends 80 of theslots 72, shaft 44 can no longer rotate in first direction 54independently of sleeve 46. Instead, if/when pins 74 reach ends 80 ofslots 72 as shown in FIG. 6, the sleeve 46 is forced to rotate withshaft 44 in direction 54, such that the shaft 44 and sleeve 46thereafter rotate together in direction 54 for the remainder of thewinding operation for the roll 14 then being made. Similarly, the innerends 82 of guide slots 72 delimit the extent to which shaft 44 canrotate in second direction 56 independently of sleeve 46 (FIG. 7).

More significantly, the extension of gripping members 48 into theengagement position shown in FIG. 6 enables them to engage the core 50and cause the core to rotate with shaft 44, thereby allowing web 12 tobe wound onto the core. In some instances, the gripping members 48 willneed to extend fully to engage the core 50, i.e., with pins 74 reachingthe ends 80 of slots 72. In other instances, e.g., when the innerdiameter of core 50 is just larger than the outer diameter of sleeve 46,the gripping members 48 will not extend fully when engaged with core 50.In such instances the pins 74 will not reach the ends 80 of slots 72;rotation of sleeve 46 will then be caused by the force of the pins 74against the side walls of the slots 72.

In some embodiments, the distal ends 68 of the gripping members 48 mayhave a roughened or knurled surface, and/or be made to have acute edgesas shown, in order to facilitate the ability of the distal ends 68 toengage, i.e., grip, the inner diameter of the roll 50.

In various embodiments of the invention, the distal ends 68 of thegripping members 48 will be within the diameter of sleeve 46 when thegripping members are in the disengagement position (FIG. 5), and willextend beyond the diameter of sleeve 46 when the gripping members are inthe engagement position (FIG. 6). In FIGS. 5-7, the diameter of sleeve46 is indicated as “D1.” As also shown, the distal ends 68 of grippingmembers 48 together form a diameter, which is indicated as D2. In FIG.5, the gripping members 48 are in the disengagement position—in thisconfiguration, it may be seen that D2 is less than D1. In FIG. 6, on theother hand, the gripping members 48 are in the engagement position,wherein D2 is greater than D1, such that the distal ends 68 extendbeyond D1 to engage the core 50.

In FIG. 7, the gripping members 48 are in the process of returning tothe disengagement position (D2<D1) via relative rotation of shaft 44 insecond direction 56, whereby core 50 may be removed from sleeve 46,e.g., when web roll 14 has reached a desired size. The operator ofsystem 10 may cause this to occur, for example, by simply pressingon/off switch 42, which cuts drive power to shaft 44. The rotationalinertia of roll 14 will cause it to continue to rotate in direction 54as shown. Because shaft 44 will then no longer be driven, the inertialrotation of roll 14 will cause its rotational speed to exceed that ofthe shaft, such that independent rotation of the shaft 44, relative tosleeve 46, in second direction 56 will occur, thereby causing thegripping members 48 to retract to the disengagement position as shown inFIG. 7.

In some embodiments of the invention, web 12 may be wound onto sleeve 46without a core 50, thereby forming a ‘core-less’ roll 14. In suchembodiments, sleeve 46 may be adapted to receive thereon web 12 suchthat the web may be wound directly onto the sleeve. The sleeve may beadapted in this regard, e.g., by being constructed of a material thatprovides sufficient friction with the web to allow at least the initialprocess of winding to begin, in some cases with some assistance by theoperator, e.g., by holding the leading edge of the web against thesleeve with a flat piece of wood or the like until the first fewoverlapped windings of the web have been created. At that point, thegripping members 48 will have moved into the engagement position toengage the web directly, i.e., upon relative rotation of shaft 44 infirst direction 54, whereby the web 12 rotates with the shaft and isthereby wound into a roll on sleeve 46. As with the previously-describedembodiments, the gripping members 48 subsequently disengage the web,i.e., move into the disengagement position, upon relative rotation ofshaft 44 in second direction 56, e.g., when the thusly-formed roll hasreached a desired size, whereby the roll may be removed from the sleeve.

Referring now to FIG. 8, additional features of the present inventionwill be described. Winding device 18 may further include a drivemechanism 84, which is schematically indicated as “D” in FIG. 8. Drivemechanism 84 is coupled to shaft 44, schematically indicated at 85,e.g., a mechanical coupling, in order to drive the rotation of the shaftat a predetermined rotational speed. In many embodiments, such speed isselected by the operator of system 10 such that the wind-up rate ofwinding device 18 approximates the rate at which the inflated web 12 issupplied by inflation/sealing apparatus 16, e.g., such that the webremains relatively taut during its transit from apparatus 16 to windingdevice 18. As the size of roll 14 increases on spool 40/core 50, therotational speed of the shaft 44 will, of necessity, decrease, for agiven web feed-rate from apparatus 16.

The drive mechanism 84 can be any conventional device capable ofproducing rotational power, such as a pneumatic, hydraulic, or electricmotor, e.g., an AC or DC motor. In some embodiments, the drive mechanismmay be an electric motor contained in base 36, and supplied with powervia power cord 86, which supplies electric power to both theinflation/sealing apparatus 16 and winding device 18.

Winding device 18 may further include a controller 88 and a sensor 90,as represented schematically in FIG. 8 as “C” and “S,” respectively. Thesensor 90 monitors the rotational speed of shaft 44, and generates andsends a corresponding signal 92 to controller 88, which is indicative ofsuch rotational speed. Based, at least in part, on signal 92, controller88 calculates a diameter of the web 12 as it is wound into roll 14 oncore 50. For example, when web 12 is supplied to spool 40 from apparatus16 at a predetermined web speed “W”, controller 88 may calculate thediameter of roll 14 (Dia₁₄) by dividing the web speed “W” by therotational speed “R” of shaft 44, as determined by sensor 90, anddividing the result by pi (π), so that:

Dia₁₄ =W/R·π

For example, if the web speed W of web 12 from apparatus 16 is 60feet/minute, and the detected rotational speed “R” of shaft 44 is 2.5revolutions/minute, 24 feet of web 12 is added to roll 14 for everyrevolution of shaft 44 (W/R=60/2.5=24), which means that thecircumference of roll 14 at that instant is 24 feet. When this number isdivided by pi (π), the diameter of roll 14 may be determined bycontroller 88 to be 7.6 feet (diameter=circumference/π).

Thus, in accordance with an embodiment of the present invention,controller 88 may be in communication with sensor 90 to receive signal92 as a first input. System 10 may be configured such that controller 88also receives, as a second input, an indication of the speed at whichweb 12 is supplied to spool 40. Such indication may be in the form of asignal 98, which may be transmitted to controller 88 by a web speedindicator 100, schematically shown as “W” in FIG. 8. Web speed indicator100 may be a web speed sensor, which physically measures the speed ofweb 12 as it moves from apparatus 16 to winding device 18.Alternatively, web speed indicator 100 may be supplied by the operatorof system 10, e.g., via a key pad or other operator interface device;may be a fixed, e.g., pre-programmed, value; or may be communicated inreal time by apparatus 16, e.g., via suitable wiring so that apparatus16 communicates with controller 88 to supply signal 98 as an indicationof the speed at which web 12 is being produced and supplied to spool 40.In this manner, controller 88 calculates a diameter of web 12 as it iswound onto core 50 to form roll 14.

Controller 88 may be in the form of a printed circuit assembly, andinclude a control unit, e.g., an electronic control unit, such as amicrocontroller, which stores pre-programmed operating codes; aprogrammable logic controller (PLC); a programmable automationcontroller (PAC); a personal computer (PC); or other such controldevice. Commands may be supplied to the controller 88 via an operatorinterface or the like, or may be supplied remotely or substantiallycompletely via pre-programming, i.e., to operate system 10 in asubstantially fully-automated fashion.

Sensor 90 may be any conventional device for detecting and counting therotations of an object, such as shaft 44, and generating a correspondingelectronic signal 92. The detection of the rotation of shaft 44 isrepresented by arrow 96. A suitable device for sensor 90 is one thatuses mechanical contact to detect rotation, such as an encoder ortachometer, or one that uses non-mechanical detection means, such as anoptical sensor, e.g., a laser-based optical sensor.

The foregoing ability of controller 88 to continuously determine thediameter of roll 14 as the roll is being produced allows winding device18 to provide a number of beneficial features in a system, such assystem 10.

For example, the controller 88 may be made operative, e.g., via suitableprogramming, to stop the rotation of shaft 44, e.g., via signal 94 todrive mechanism 84, when the diameter of the web 12 as roll 14 on core50 reaches a predetermined value. This frees the operator of system 10to perform other tasks, i.e., instead of idly monitoring system 10 topress on/off switch 42 when the diameter reaches the predeterminedvalue. For instance, if a roll diameter of 8 feet is desired, thecontroller will send signal 94 to drive mechanism 84, causing the drivemechanism to cease driving the rotation of shaft 44, e.g., via asuitable electronic switch (transistor or the like), which acts as anon/off switch for the supply of power to the drive mechanism. Suchsignal 94 would preferably also cause apparatus 16 to cease operation,e.g., via the same electronic switch as for drive mechanism 84, throughwhich power supplied by power cord 86 may flow to both the apparatus 16and winding device 18. When convenient, the operator can then remove theroll 14, insert another core 50 on spool 40, attach the end of a web 12to the core, and then cause power to once again be supplied to apparatus16 and winding device 18 to begin the production of a new roll 14.

As another example, the controller 88 may be operative to vary theoutput of drive mechanism 84 in order to maintain a substantiallyconstant tensional force on the web 12 as it is wound onto core 50. Thatis, in order to wind web 12 onto spool 40/core 50, the drive mechanism84 applies torque to the spool 40, thereby producing a tensional force102 on web 12 as it is wound onto the core 50. One of the challenges ofmaking large rolls 14, e.g., having diameters in excess of about fourfeet, e.g., 6 or even 8 feet, from inflated cushioning material 20, isthat such rolls tend to be uneven and/or loosen, which leads todifficulty in handling the rolls for storage and subsequent use, e.g.,often resulting in the material 20 falling off of the roll. Theinventors have found that large rolls 14 of inflated cushioning material20 can be can be successfully made when the web 12 remains under asubstantially constant tensional force. This results in a uniform,tightly-wound roll 14.

However, the torque required of drive mechanism 84 to provide a constanttensional force on web 12 changes continuously as the diameter of theroll 14 increases. In order to solve this problem in accordance withanother embodiment of the invention, controller 88 may be operative tocause the drive mechanism 84 to increase the torque applied to spool 40in proportion to the increase in the diameter of web 12 on core 50 asroll 14 is being formed. This allows the tensional force 102 of web 12to be controlled, even as the diameter of roll 14 continuouslyincreases.

As an example, if an operator of system 10 determines that a tensionalforce 102 of 3 pounds produces a roll 14 of desired tightness anduniformity, and apparatus 16 produces web 12 at a web speed W of 60feet/minute, the initial rotational speed R of shaft 44, as determinedby sensor 90, may be 20 revolutions/minute. Applying the formulaDia₁₄=W/R·π, the diameter of the roll 14 at that time will be 0.95 feet.Given that:

Torque(“T”)=Force(“F”)·Length(“L”),

and that “L” in this case is the radius of the roll 14, which is foundby dividing Dia₁₄ by 2, resulting in a radius (L) of 0.47 feet. Thus, inorder to achieve a tensional force (F) of 3 pounds when the rolldiameter is 0.95 feet, the above formula, T=F·L, is applied to result ina torque (T) of 1.4 foot-pounds (T=3 pounds·0.47 feet=1.4 foot-pounds).Accordingly, controller 88, which has made the foregoing calculation,will command drive mechanism 84 to apply a torque of 1.4 foot-poundsduring the instant that the calculated diameter of roll 14 is 0.95 feet,thereby achieving a tensional force 102 on web 12 of 3 pounds.

Later, as roll 14 has grown, sensor 90 may detect a rotational speed Rof shaft 44 of 2.5 revolutions/minute. With apparatus 16 continuing tosupply web 12 at a rate of 60 feet/minute, according to the formula,Dia₁₄=W/R·π, this rotational speed corresponds to a roll diameter of 7.6feet, or a radius of 3.8 feet. Applying the formula, T=F·L, the torquerequired of drive mechanism 84 to achieve a tensional force in the webof 3 pounds is 14.25 foot-pounds, which controller 88 will command thedrive mechanism to provide.

Accordingly, the tensional force 102 of web 12 may be controlled at adesired value, even as the diameter of roll 14 continuously increases.

A further feature of the invention is that the controller 88 may beadapted, e.g., programmed, to cause the drive mechanism 84 to stop therotation of shaft 44, e.g., via signal 94 to drive mechanism 84, whenthe detected rotational speed “R” of shaft 44/spool 40 exceeds, ordecreases below, a predetermined value. For example, a sudden increasein R could result from the breakage of web 12. As another example, asudden decrease in R could result from a web jam or other malfunction,in either the inflation/sealing apparatus 16 or in winding device 18.Thus, the predetermined value to be programmed into controller 88 couldbe, e.g., a change in R of 20% or more, which occurs over a period of,e.g, 5 seconds or less.

The foregoing description of preferred embodiments of the invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed, and modifications and variations are possible in light of theabove teachings or may be acquired from practice of the invention.

1. A winding device comprising a spool, said spool comprising: a. ashaft; b. a sleeve rotatably coupled to said shaft such that said sleeveand said shaft are capable of partial independent rotation relative toone another, said sleeve enclosing at least a portion of said shaft andadapted to receive thereon a core, onto which a web of material may bewound; and c. one or more gripping members, which are adapted to engagethe core upon relative rotation of said shaft in a first direction,whereby the core rotates with said shaft to allow the web to be woundonto the core, said gripping members being further adapted to disengagethe core upon relative rotation of said shaft in a second direction,whereby said core may be removed from said sleeve.
 2. The device ofclaim 1, wherein said shaft is coupled to said sleeve via a rotarymounting bracket.
 3. The device of claim 2, wherein said shaft isrotatably mounted in said bracket; and said bracket is affixed tosleeve.
 4. The device of claim 3, wherein said gripping members areattached to said shaft; and part of each gripping member moves away fromsaid shaft and into an engagement position, in which said grippingmembers engage the core, when said shaft rotates in said firstdirection.
 5. The device of claim 4, wherein said gripping members arepivotally attached to said shaft; said bracket includes one or moreguide slots; and each of said gripping members includes a guide pin,which is movable within one of said guide slots to facilitate movementof said gripping members into said engagement position.
 6. The device ofclaim 4, wherein said part of said gripping members that are in saidengagement position move towards said shaft and into a disengagementposition, in which said gripping members disengage the core, when saidshaft rotates in said second direction.
 7. The device of claim 4,wherein said gripping members have a proximal end and a distal end; saidproximal end is attached to said shaft; said distal end moves away fromsaid shaft and into said engagement position when said shaft rotates insaid first direction; and said distal end moves towards said shaft andinto said disengagement position when said shaft rotates in said seconddirection.
 8. The device of claim 7, wherein said sleeve has a diameterD1; said distal ends of said gripping members together form a diameterD2; D2 is greater than D1 when the distal ends of said gripping membersare in said engagement position; and D2 is less than D1 when the distalends of said gripping members are in said disengagement position.
 9. Thedevice of claim 1, further including a drive mechanism coupled to saidshaft to drive the rotation thereof at a predetermined rotational speed.10. The device of claim 9, further including a controller and a sensor,wherein said sensor monitors the rotational speed of said shaft andsends a corresponding signal to said controller; and based, at least inpart, on said signal, said controller calculates a diameter of the webas it is wound onto the core.
 11. The device of claim 10, wherein saidcontroller is operative to stop the rotation of said shaft upon theoccurrence of at least one of the following events: a. said diameter ofthe web on the core reaches a predetermined value; and b. the rotationalspeed of said shaft exceeds, or falls below, a predetermined value. 12.The device of claim 10, wherein said controller is operative to vary theoutput of said drive mechanism in order to maintain a substantiallyconstant tensional force on the web as it is wound onto the core. 13.The device of claim 10, wherein said device is adapted to wind a webcomprising an inflated cushioning material onto the core.
 14. A windingdevice, comprising: a. a spool adapted to receive thereon a core, ontowhich a web of material may be wound, the web being supplied to saidspool at a predetermined speed; b. a drive mechanism coupled to saidspool to drive the rotation thereof at a predetermined rotational speed;c. a sensor, which monitors the rotational speed of said spool andgenerates a signal indicative of said rotational speed; and d. acontroller in communication with said sensor to receive said signal as afirst input, said controller also receiving, as a second input, anindication of the speed at which the web is supplied to said spool,wherein, said controller calculates a diameter of the web as it is woundonto the core.
 15. The device of claim 14, wherein said controller isoperative to stop the rotation of said spool upon the occurrence of atleast one of the following events: a. said diameter of the web on thecore reaches a predetermined value; and b. the rotational speed of saidspool exceeds, or falls below, a predetermined value.
 16. The device ofclaim 14, wherein said drive mechanism applies torque to said spool,thereby producing a tensional force on the web as it is wound onto thecore; and said controller is operative to cause said drive mechanism toincrease said torque in proportion to an increase in the diameter of theweb on the core to thereby control said tensional force.
 17. A windingdevice comprising a spool, said spool comprising: a. a shaft; b. asleeve rotatably coupled to said shaft such that said sleeve and saidshaft are capable of partial independent rotation relative to oneanother, said sleeve enclosing at least a portion of said shaft andadapted to receive thereon a web of material such that the web may bewound onto said sleeve; and c. one or more gripping members, which areadapted to engage the web upon relative rotation of said shaft in afirst direction, whereby the web rotates with said shaft and is therebywound into a roll on said sleeve, said gripping members being furtheradapted to disengage the web upon relative rotation of said shaft in asecond direction, whereby the roll may be removed from said sleeve.